Many manufacturing processes, such as those in the field of microelectronics, require the use of various acids and chemicals in liquid form. These liquids are extremely hazardous to human operators, and are also a potential contaminant to the work environment (such as a clean room) if not properly contained.
Typically, the liquids are held in large tanks, which supply their contents to the manufacturing process, on demand from a system controller. When the liquid level in a tank falls below a pre-determined "low" level, it must be replenished to maintain the production process. Traditionally, manual surveillance was used to detect the need for replenishment. Once this need was determined, the task of replenishing the liquid was accomplished manually by maintenance personnel. Due to the hazardous nature of the liquid, there was a constant danger to personnel, as well as to the integrity of the manufacturing environment. In addition, the production process would normally be shut down during the replenishment period.
It is an object of the present invention, therefore, to eliminate the aforementioned danger to manufacturing personnel by automating the replenishment task. The disclosed automated procedure precludes the need for human intervention in the maintenance of adequate liquid levels in the liquid containment tanks.
It is a further object of the present invention to protect the working environment area adjacent to the liquid tanks during the liquid replenishment process.
It is another object of the present invention to minimize downtime of the production process during the hazardous liquid replenishment process.